Iranian men have been banned from wearing necklaces in the latest crackdown by the Islamic regime on "un-Islamic" clothing and haircuts.

Thousands of special forces have been deployed in Tehran's streets, participating in the regime's "moral security plan" in which loose-fitting headscarves, tight overcoats and shortened trousers that expose skin will not be tolerated for women, while men are warned against glamorous hairstyles and wearing a necklace.

The new plan comes shortly after the Iranian parliament proposed a bill to criminalise dog ownership, on the grounds that it "poses a cultural problem, a blind imitation of the vulgar culture of the west".

The Irna state news agency said the trend was aimed at combating "the western cultural invasion" with help from more than 70,000 trained forces, known as "moral police", who are sent out to the streets in the capital and other cities.

With the summer heat sweeping across the country, many people, especially the young, push the boundaries and run the risk of being fined, or even arrested, for wearing "bad hijab" clothing.

Women in particular are under more pressure because of the restriction on them to cover themselves from head to toe. Men are allowed to wear short-sleeved shirts, but not shorts.

"The enforcement of the moral security plan was requested by the nation and it will be continued until people's concerns are properly addressed," said Ahmadreza Radan, the deputy commander of the Iranian police.

Iran's moral police usually function under a body whose head is appointed directly by the supreme leader, Ayatollah Ali Khamenei. In a live television programme last year, president Mahmoud Ahmadinejad said that he did not approve of the crackdown.

Speaking by phone, a Tehran resident, who asked to remain anonymous, said: "It's not only about clamping down on clothing, but they are spreading panic and fear by sending out this much of police into the streets under the name of this plan, to control the society. It's unbelievable to see a regime that is not only concerned about its own survival but it goes into your personal life and interferes in that."

Under Islamic customs, dogs are deemed to be "unclean". Iranians, in general, avoid keeping them at home, but still a minority, especially in north Tehran's upper-class districts, enjoy keeping pets. Last year Ayatollah Makarem Shirazi, a prominent hardline cleric, issued a fatwa against keeping dogs and said the trend must stop.

Last summer authorities in Tehran also released a list of approved hairstyles in an attempt to offer Islamic substitutes to "decadent" western cuts, such as the ponytail and the mullet.